Renesas 83940DYILFT

Overview

83940DYILFT from Renesas Electronics is a low-skew 1-to-18 LVPECL-to-LVCMOS/LVTTL fanout buffer with dual selectable clock inputs (LVCMOS_CLK or PCLK/nPCLK), 18 single-ended outputs, 250 MHz maximum output frequency, and guaranteed 150 ps max output skew. It supports mixed 3.3 V core / 2.5 V output operation and is used in high-reliability clock distribution for telecom infrastructure and industrial control systems.

For engineers reviewing the 83940DYILFT datasheet, 83940DYILFT pinout, 83940DYILFT application, or 83940DYILFT equivalent, this page delivers verified electrical specs, LQFP-32 pin mapping, real-world timing performance under 3.3 V/2.5 V supply modes, and validated alternatives for legacy design continuity.

Technical Context

The 83940DYILFT implements a dual-input multiplexer architecture: CLK_SEL selects between LVCMOS_CLK (single-ended) and PCLK/nPCLK (differential), with internal pullup/pulldown resistors (51 kΩ) on all control and clock inputs. Its output stage drives 50 Ω series- or parallel-terminated lines with 18–28 Ω typical output impedance.

It operates across three supply configurations-3.3 V/3.3 V, 3.3 V/2.5 V, and 2.5 V/2.5 V-with distinct AC performance: at 3.3 V/2.5 V, it achieves 250 MHz f_MAX, 150 ps max t_sk(o), and 750 ps max part-to-part skew; at 2.5 V/2.5 V, f_MAX drops to 200 MHz and t_sk(o) increases to 200 ps.

Key Specifications

Pinout & Package

83940DYILFT uses a lead-free 32-lead LQFP package (7 mm × 7 mm × 1.4 mm body, Y package). The exposed pad is electrically connected to GND and requires thermal vias for optimal heat dissipation and signal integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar clock fanout applications.

Compared with 83940DYILFT, 87016I removes differential input capability but offers RoHS-compliant availability beyond discontinuation, while ICS83941DYILFT retains full functional and pin compatibility with measurable improvements in skew and 2.5 V-mode frequency - making it the preferred drop-in replacement where supported.

Availability

83940DYILFT is available at Aetrix Electronics and suitable for telecom infrastructure, industrial automation, and medical imaging systems requiring stable component supply during legacy design support and obsolescence transition phases.

Supply support for 83940DYILFT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Renesas Electronics is a global semiconductor leader specializing in microcontrollers, analog, power, and timing solutions for automotive, industrial, and communications markets.

The ICS83940DI family was designed specifically for high-reliability, low-skew clock distribution in multi-protocol systems requiring LVPECL-to-LVCMOS conversion and flexible supply voltage operation.

FAQ

What is the maximum operating frequency of the 83940DYILFT under 3.3 V core / 2.5 V output conditions?

The 83940DYILFT supports a maximum output frequency of 250 MHz when operated with VDD = 3.3 V ± 5% and VDDO = 2.5 V ± 5%, as specified in Table 5B of the Renesas datasheet. This performance enables use in PCIe Gen1/Gen2 reference clock distribution and high-speed serial interface timing applications where precise edge placement is critical. The 83940DYILFT maintains 150 ps maximum output skew even at this frequency.

Does the 83940DYILFT support differential clock inputs, and what standards are compatible?

Yes, the 83940DYILFT supports differential clock inputs via the PCLK/nPCLK pair, which is explicitly characterized for LVPECL, CML, and SSTL signaling levels. Input specifications include peak-to-peak voltage (V_PP) of 300–1000 mV and common-mode range (V_CMR) of VDD − 1.4 V to VDD − 0.6 V. These parameters ensure interoperability with standard 3.3 V LVPECL drivers, 2.5 V CML transceivers, and SSTL-2 memory clock sources without external level shifting.

How does the CLK_SEL pin function in the 83940DYILFT, and what happens when it is left unconnected?

The CLK_SEL pin on the 83940DYILFT is an active-HIGH control that selects the clock source: HIGH enables the LVCMOS_CLK input, while LOW enables the PCLK/nPCLK differential pair. Pin 4 has an internal pulldown resistor (51 kΩ), so an unconnected CLK_SEL defaults to LOW, selecting the differential input path. This behavior is confirmed in Table 1 (Pin Descriptions) and Table 3A (Clock Select Function Table) of the official datasheet for the 83940DYILFT.

What package type and footprint does the 83940DYILFT use, and are thermal vias required?

The 83940DYILFT uses a lead-free 32-lead LQFP package (7 mm × 7 mm × 1.4 mm body, Y package) with a standard JEDEC outline (PRG32D1). Although the package lacks an exposed thermal pad, Renesas' thermal characterization data (Table 6A) confirms θ_JA = 39.4°C/W at 500 LFPM airflow on multilayer PCBs - validating standard LQFP thermal design practices. No thermal vias are required, but proper ground plane connection to all five GND pins (pins 1, 2, 12, 17, 25) is essential for EMI control and skew stability in the 83940DYILFT.

Is the 83940DYILFT still in production, and what is its lifecycle status?

The 83940DYILFT is a discontinued product with Last Time Buy expired May 6, 2017, as documented in Renesas Product Discontinuation Notice PDN CQ-16-01. However, Aetrix Electronics maintains legacy inventory and provides controlled supply for ongoing production and repair programs. For long-term design continuity, Renesas recommends the pin-compatible ICS83941DYILFT as a functional upgrade, and the 87016I as a simplified alternative for LVCMOS-only applications - both confirmed in the official 83940DYILFT datasheet revision history.